1. Field of the Invention
The present invention relates to a communication apparatus that communicates with an external apparatus and a method for controlling the communication apparatus.
2. Description of the Related Art
There has been known a communication apparatus including a communication unit to perform magnetic-field communication with an external apparatus by using the principle of electromagnetic induction. This communication unit includes an Radio Frequency Identification (RFID) chip or the like, which is a noncontact Integrated Circuit (IC) chip.
The conventional communication unit includes a magnetic-field antenna or the like, and a resonance (tuning) frequency to perform magnetic-field communication with an external apparatus, where the frequency to resonate with the external apparatus is predetermined to be within a certain range. Thus, adjustment of the resonance frequency has been required. For example, it has been known to apply a conductive material onto a magnetic-field antenna for RFID in a step of assembling a communication apparatus so as to change the inductance value of the magnetic-field antenna and to adjust the resonance frequency.
Also, it has been known to provide a function of adjusting a resonance frequency using a trimmer capacitor or the like on a circuit board, form a hole or the like in a casing so that the trimmer capacitor can be adjusted from the outside of a communication unit, and adjust the resonance frequency in a resonance frequency adjusting step before factory shipment. Because the resonance frequency for magnetic-field communication with an external apparatus varies in respective communication units, the above-described resonance frequency adjusting step is required to be performed on the respective communication units, which is wasteful.
Accordingly, a communication apparatus capable of preferably adjusting the resonance frequency of a communication unit without the necessity of such wasteful adjustment and a method for controlling the communication apparatus have been demanded.